The invention relates to an arrangement for fastening pocket clips to tubular parts of writing instruments such as ball-point pen casing parts, fountain pen caps or the like, wherein the pocket clip which has a tongue stamped from metal strip material and fastened at its upper end to the tubular part, the bottom end of the tongue being urged resiliently against the tubular part; at its upper end the clip has two tabs of material bent back from its opposite longitudinal margins toward the tubular part and pressed through a mating, substantially rectangular opening in the tubular part into the interior of the tubular part, where they are secured against complete withdrawal from the rectangular opening.
The fastening of pocket clips to casings of ball-point pens or to the caps of fountain pens was originally performed by means of a ring formed at the upper end of the clip and set at right angles to the tongue of the clip; this ring was held between two casing parts screwed, glued or otherwise joined together. The mounting of pocket clips on tubular casing parts, such as ball-point pen casings injection molded from plastic, was substantially simplified by providing at the upper end of the tongue a tab having lateral, rearwardly inclined tooth projections which are inserted into a complementary opening formed in the casing part and locked against withdrawal by the tooth projections penetrating into the plastic material. In the case of thin-walled tubular parts of metal, however, such fastening of the pocket clip is not possible.
U.S. Pat. No. 2,276,891 discloses a fastening arrangement in which the lug formed at the upper end of the tongue by prolonging its web portion is introduced through a slot in the tubular part and then bent downwardly onto the inner side of the wall of the tubular part. The lug is then affixed by means of additional lugs likewise brought through slots in the wall of the tubular part and bent across the tongue. The lugs serve exclusively to produce a very rigid fastening of the pocket clip to the tubular part. The resilient holding force must therefore be assured by making the clip appropriately spring-elastic. At the same time, however, the pocket clip itself must be sufficiently stable so that it cannot be accidentally overstretched to such an extent that its pocket-holding end no longer springs back against the tubular part of the writing instrument. Consequently, either a relatively thick sheet-metal material must be used in making the pocket clip, or it must be made sufficiently resistant to permanent deformation by appropriately shaping its cross section. This, however, necessarily makes the spring force urging the pocket-holding end of the clip against the tubular part of the writing instrument high, which does assure that the writing instrument will be held tightly and securely in a pocket or the like, but at the same time makes it inconvenient to use and can also do damage to portions of garments gripped between the tongue and the tubular casing part.
The invention, on the other hand, is addressed to the problem of creating an arrangement for fastening pocket clips to tubular parts of writing instruments which can consist either of plastic or of thin metallic material, which will permit a quick and easy fastening of the previously made pocket clip with a relatively stiff tongue, i.e., one not resiliently flexible to a sufficient degree, to an associated tubular part, while the gripping force produced between the tongue and the tubular part is to be low in comparison, so that the free, clasping end of the tongue can easily be slipped over the outer margin of the pocket when the writing instrument is inserted into the pocket of a garment.